This invention relates to improvements in microscope objectives, and in particular to a semi-apochromatic microscope objective with a numerical aperture of substantially 0.80, and a magnification of substantially 40x when used with a telescope lens. It is the object of this invention to provide such a microscope objective in which the usual chromatic image aberrations are exceptionally well-corrected as well as spherical aberration, coma, and astigmatism, while having a substantially flat image over a 20 millimeter field when used with telescope as described in U.S. Pat. No. 3,355,234 and a typical 10x eyepiece.